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Reply With QuoteMine PSU is isolated type - look at links in my signature
Are there any DC-to-DC PSUs on the market that *don't* have the battery negative terminal bridged to the PC's internal ground? Such a PSU sitting by itself (no connections hooked up) would show no continuity / infinite resistance between ATX black wires and the incoming negative lead.
This type of design can be very helpful in reducing ground loop problems. My very old (AMD K6/233) carputer has one, built up from individual DC-DC "quarter brick" modules, originally intended for telecom use (easier to do in the pre-ATX days). These run all incoming power through high-frequency transformers, similar to the front end of an inverter, or an AC->DC switchmode PSU.
One tradeoff is slightly reduced efficiency from the extra transformer stage.
The M2-ATX is a simple buck converter design, with battery negative bonded to PC ground.
Is a DSATX similar? From looking at pictures of the board, it appears to be a buck converter also. Does anyone have a photo of the bottom (trace side) to confirm?
Any other options? An inverter feeding a normal AC-DC PSU would be one way, but those have enough problems of their own. Maybe a 12V->12V isolated DC-DC (hard to find one with sufficient amperage) as a front end to something like the mini-box PWR200?
400Watt CarPC power supply for powerfull systems- thaks for Beta testers- it was perfect.
Remember - AMD Athlon XP (socket A) powers from 5v rail in most times !
Mastervolt, DC-DC converter Magic (12/12-20)
Isolated 300W
Only found one place online and it was from denmark? and 500 euro. ouch.
And importing one to the US would only compound the "ouch" factor...Originally Posted by Beehphy
Still, that looks like a nice little unit, at 90-92% efficiency. If only they had a cheaper model without so many extra features (light dimmer function, 3-stage battery charging...)
One idea I've thought about is to modify a cheap MSW inverter for high-voltage DC output (taking 140-170VDC directly from the first filter section, and bypassing/removing the "chopper" part that generates alternating +/- AC pulses), and feeding that into a conventional AC ATX PSU, most of which are happy enough running on DC power near the AC peak voltage (not RMS; 120VAC RMS goes to about +/- 170V peak). This DC could be injected beyond the AC PSU's bridge rectifier, avoiding diode drop losses there.
Losing the inverter's chopper section should remove any 60/120/180Hz buzzing noise from the system-- the AC PSU would see only clean, stable DC, perhaps with some very high frequency ripple on top from the inverter's 1st stage. With a good PSU, overall efficiency could be 75-80% or better, not too much worse than with a non-isolated DC-DC.
I've done this successfully for smaller loads, such as CFL lights and satellite receivers. Power supplies with active PFC, or automatic 120/240V switching probably won't like the DC as well, though.
Trying to import this to US would only add to the "ouch" factor... interesting find, though, and the 90-92% efficiency is better than average. If only they'd make a less expensive, scaled down version without so many features (light dimming, 3-stage battery charging...)
http://www.powerstream.com/
This is 100% Isolated. I use the PSCT-400watt and it's got great amperage on the rails. Gotta tell ya that I've had no problems with it this winter but not long enough to comment about it in warm season. I get great sound in my system which is due to the way it controls and maintains it's amperage on the rails. I check the voltages in my bios and it displays no fluctuations. The 12v rail is 12.03 to 12.01 which is normal.
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